Intracellular distribution of nitrogen during synchronous growth of Chlorella pyrenoidosa

A continuous dilution method for the mass culture of microorganisms was developed which yielded 3x as much cellular material as previous culturing methods for <i>C. pyrenoidosa</i> in the same time period and in less than one-tenth the culture volume. Cellular growth parameters increased exponentially throughout the cell cycle of <i>C. pyrenoidosa</i> when the new mass culturing technique was utilized. The levels of nitrogen in different cellular fractions were estimated during the cell cycle (i.e. lipid-plus chlorophyll-N; TCA soluble-N; individual free-, peptide-, and protein-amino acid residues; nucleotide-N; DNA-N; RNA-N). The amino acid distribution within the cellular protein remained nearly constant during cellular development. Protein-N accounted for approximately 60% of the total cellular-N throughout the cell cycle. The free amino acids exhibited a variety of trends in change of level during the cell cycle. Free-alanine, -lysine, -serine, -glycine, -arginine, and -glutamate were present at relatively high levels. Increase in level of peptide-N during early cellular development resulted largely from increase in levels of peptide-arginine, -glutamate, and -lysine. The other peptide amino acids exhibited a variety of different trends. RNA-N demonstrated exponential accumulation throughout cellular development with a reduced rate of accumulation during cellular division. DNA-N increased during most of the cell cycle at a lower exponential rate; however, the rate of DNA-N accumulation increased abruptly at the onset of nuclear division. Reduced glutathione (GSH) was found to be the predominant acid-soluble sulfhydryl-containing compound throughout the cell cycle. Its trend (as % of total cellular-N) was similar to that of TCA-soluble sulfhydryl-containing compounds in synchronized sea urchin eggs. GSH exhibited properties similar to certain compounds tentatively identified as sulfur-containing nucleotide-peptides by previous workers. Norit-A adsorption studies indicated that nucleotide-peptides were not present in the TCA extracts of <i>C, pyrenoidosa.</i> During the period 0.4-0.9 fraction of the cell cycle GSH was synthesized at the expense of cellular protein. A hypothetical scheme was presented to account for both the origin of GSH prior to nuclear division and the proposed regulation of mitotic apparatus formation through acid-soluble sulfhydryl compounds.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Biochemistry and Nutrition

Department dc:contributor.department

Biochemistry and Nutrition

Grantor dc:publisher

Virginia Polytechnic Institute

Year dc:date.issued

1967

Author dc:creator

• Hare, Theodore Arthur

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10919/121593

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/121593